Search Results

Search found 6707 results on 269 pages for 'reinforcement learning'.

Page 236/269 | < Previous Page | 232 233 234 235 236 237 238 239 240 241 242 243  | Next Page >

  • How to update a Widget dynamically (Not waiting 30 min for onUpdate to be called)?

    - by Donal Rafferty
    I am currently learning about widgets in Android. I want to create a WIFI widget that will display the SSID, the RSSI (Signal) level. But I also want to be able to send it data from a service I am running that calculates the Quality of Sound over wifi. Here is what I have after some reading and a quick tutorial: public class WlanWidget extends AppWidgetProvider{ RemoteViews remoteViews; AppWidgetManager appWidgetManager; ComponentName thisWidget; WifiManager wifiManager; public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { Timer timer = new Timer(); timer.scheduleAtFixedRate(new WlanTimer(context, appWidgetManager), 1, 10000); } private class WlanTimer extends TimerTask{ RemoteViews remoteViews; AppWidgetManager appWidgetManager; ComponentName thisWidget; public WlanTimer(Context context, AppWidgetManager appWidgetManager) { this.appWidgetManager = appWidgetManager; remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget); thisWidget = new ComponentName(context, WlanWidget.class); wifiManager = (WifiManager)context.getSystemService(Context.WIFI_SERVICE); } @Override public void run() { remoteViews.setTextViewText(R.id.widget_textview, wifiManager.getConnectionInfo().getSSID()); appWidgetManager.updateAppWidget(thisWidget, remoteViews); } } The above seems to work ok, it updates the SSID on the widget every 10 seconds. However what is the most efficent way to get the information from my service that will be already running to update periodically on my widget? Also is there a better approach to updating the the widget rather than using a timer and timertask? (Avoid polling) UPDATE As per Karan's suggestion I have added the following code in my Service: RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget); ComponentName thisWidget = new ComponentName( context, WlanWidget.class ); remoteViews.setTextViewText(R.id.widget_QCLevel, " " + qcPercentage); AppWidgetManager.getInstance( context ).updateAppWidget( thisWidget, remoteViews ); This gets run everytime the RSSI level changes but it still never updates the TextView on my widget, any ideas why?

    Read the article

  • How to get at JSON in grails 2.0

    - by Mikey
    I am sending myself JSON like so with jQuery: $.ajax ({ type: "POST", url: 'http://localhost:8080/myproject/myController/myAction', dataType: 'json', async: false, //json object to sent to the authentication url data: {"stuff":"yes", "listThing":[1,2,3], "listObjects":[{"one":"thing"},{"two":"thing2"}]}, success: function () { alert("Thanks!"); } }) I send this to a controller and do println params And I know I'm already in trouble... [stuff:yes, listObjects[1][two]:thing2, listObjects[0][one]:thing, listThing[]:[1, 2, 3], action:myAction, controller:myController] I cannot figure out how to get at most of these values... I can get "yes" with params.stuff, but I cant do params.listThing.each{} or params.listObjects.each{} What am I doing wrong? UPDATE: I make the controller do this to try the two suggestions so far: println params println params.stuff println params.list('listObjects') println params.listThing def thisWontWork = JSON.parse(params.listThing) render("omg l2json") look how weird the parameters look at the end of the null pointer exception when I try the answers: [stuff:yes, listObjects[1][two]:thing2, listObjects[0][one]:thing, listThing[]:[1, 2, 3], action:l2json, controller:rateAPI] yes [] null | Error 2012-03-25 22:16:13,950 ["http-bio-8080"-exec-7] ERROR errors.GrailsExceptionResolver - NullPointerException occurred when processing request: [POST] /myproject/myController/myAction - parameters: stuff: yes listObjects[1][two]: thing2 listObjects[0][one]: thing listThing[]: 1 listThing[]: 2 listThing[]: 3 UPDATE 2 I am learning things, but this can't be right: println params['listThing[]'] println params['listObjects[0][one]'] prints [1, 2, 3] thing It seems like this is some part of grails new JSON marshaling. This is somewhat inconvenient for my purposes of hacking around with the values. How would I get all these individual params back into a big groovy object of nested maps and lists? Maybe I am not doing what I want with jQuery?

    Read the article

  • How do I debug JavaScript .onlick event?

    - by user3700824
    I'm learning JavaScript but seem to be having a problem. I have a piece of code that is executed when the page is fully loaded. The function then gathers all the button elements on my HTML page. From here I loop through getting each button's title attribute and then assign an onclick event to the button that is equal to a function that writes to the console.log with the title. I have tried various ways of doing this but it is not working. Here is the JavaScript code that I'm working with. Currently all it does is loop through calling the function and logging the tile to the console.log, but this is not supposed to happen. Each time I click the button it should call the function with its title and log that. window.onload = myPageIsReady; function myPageIsReady(){ var myList = document.getElementsByTagName("button"); var myTitle = []; for(var i = 0; i < myList.length; i++){ myTitle[i] = myList[i].getAttribute("title"); myList[i].onclick = getMyTitle(myTitle[i]); }; function getMyTitle(myTitle){ console.log(myTitle); }; };

    Read the article

  • Is going for a BCS the right move for me?

    - by Michel Carroll
    I'm at a fork in the road. I need somebody to give me some advice from their personal journey in IT. At the moment, I have a college diploma (2 years) in Computer Programmer, and about 2 years of professional experience in the field of software. I'm currently freelancing my programming skills to the public, and am enjoying a nice income, and the rewards of flexibly working on a variety of projects with different cool people. I'm young (21 years old), passionate about software, technology, the internet, and also business. I know if I ever want to dwell deeper into the software industry, I might have a hard time doing so without a Bachelors in Computer Science. On one side, I think I'm better off getting my BCS while I'm still young and malleable. Also, the thought of learning even more stuff in my field is really exciting to me. On the flip side, it means another 3-4 years of studying, and jeopardizing my chances of going on vacation and accumulating wealth for a long time. Considering that I'm already pretty successful with my college diploma, do you think it's a good idea for me to go get my BCS? Will it open up many more doors in the future?

    Read the article

  • I getting undefined using JSON in jQuery why?

    - by YoniGeek
    Im learning some JSON, Im trying to list some data about dogs from twitter...but I can't really present the data...I believe that the error is inside map-method...something I'm missing...thanks for yr help <body> <h1>U almost there!!</h1> <script src="jquery-1.7.1.js"> </script> <script> // PubSub (function( $ ) { var o = $( {} ); $.each({ trigger: 'publish', on: 'subscribe', off: 'unsubscribe' }, function( key, val ) { jQuery[val] = function() { o[key].apply( o, arguments ); }; }); })( jQuery ); $.getJSON('http://search.twitter.com/search.json?q=dogs&callback=?', function( info) { $.publish( 'twitter/info', info ); }); // ... $.subscribe( 'twitter/info', function( e, info ) { $('body').html( $.map( info, function( obj) { // <--- here it's error, something Im missing right? return '<li>' + obj.text + '</li>'; }).join('') ); }); </script> </body> </html>

    Read the article

  • How does DATEDIFF calculate week differences in SQL Server 2005?

    - by eksortso
    I would like to calculate the difference in weeks between two dates, where two dates are considered part of the same week if their preceding Sunday is the same. Ideally, I'd like to do this using DATEDIFF, instead of learning an elaborate idiom to calculate the value. But I can't tell how it works when weeks are involved. The following query returns 1 and 2. This might make sense if your calendar week begins with a Sunday, i.e. if you run SET DATEFIRST 7 beforehand or if @@DATEFIRST is 7 by default. SET DATEFIRST 7; -- SET DATEFIRST 1; DECLARE @d1 DATETIME, @d2a DATETIME, @d2b DATETIME ; SELECT @d1 = '2010-04-05', -- Monday @d2a = '2010-04-16', -- Following Friday @d2b = '2010-04-18' -- the Sunday following ; SELECT DATEDIFF(week, @d1, @d2a) AS weekdiff_a -- returns 1 ,DATEDIFF(week, @d1, @d2b) AS weekdiff_b -- returns 2 ; So I expected different results if SET DATEFIRST 1 is executed instead of SET DATEFIRST 7. But the return values are the same, regardless! What is going on here? What should I do to get the correct week differences?

    Read the article

  • Does everything after my try statement have to be encompassed in that try statement to access variab

    - by Mithrax
    I'm learning java and one thing I've found that I don't like, is generally when I have code like this: import java.util.*; import java.io.*; public class GraphProblem { public static void main(String[] args) { if (args.length < 2) { System.out.println("Error: Please specify a graph file!"); return; } FileReader in = new FileReader(args[1]); Scanner input = new Scanner(in); int size = input.nextInt(); WeightedGraph graph = new WeightedGraph(size); for(int i = 0; i < size; i++) { graph.setLabel(i,Character.toString((char)('A' + i))); } for(int i = 0; i < size; i++) { for(int j = 0; j < size; j++) { graph.addEdge(i, j, input.nextInt()); } } // .. lots more code } } I have an uncaught exception around my FileReader. So, I have to wrap it in a try-catch to catch that specific exception. My question is does that try { } have to encompass everything after that in my method that wants to use either my FileReader (in) or my Scanner (input)? If I don't wrap the whole remainder of the program in that try statement, then anything outside of it can't access the in/input because it may of not been initialized or has been initialized outside of its scope. So I can't isolate the try-catch to just say the portion that intializes the FileReader and close the try statement immediately after that. So, is it the "best practice" to have the try statement wrapping all portions of the code that are going to access variables initialized in it? Thanks!

    Read the article

  • Java queue and multi-dimention array question? [Beginner level]

    - by javaLearner.java
    First of all, this is my code (just started learning java): Queue<String> qe = new LinkedList<String>(); qe.add("b"); qe.add("a"); qe.add("c"); qe.add("d"); qe.add("e"); My question: Is it possible to add element to the queue with two values, like: qe.add("a","1"); // where 1 is integer So, that I know element "a" have value 1. If I want to add a number let say "2" to element a, I will have like a = 3. If this cant be done, what else in java classes that can handle this? I tried to use multi-dimention array, but its kinda hard to do the queue, like pop, push etc. (Maybe I am wrong) How to call specific element in the queue? Like, call element a, to check its value. [Note] Please don't give me links that ask me to read java docs. I was reading, and I still dont get it. The reason why I ask here is because, I know I can find the answer faster and easier.

    Read the article

  • Android - Parsing XML with XPath

    - by Ruben Deig Ramos
    First of all, thanks to all the people who's going to spend a little time on this question. Second, sorry for my english (not my first language! :D). Well, here is my problem. I'm learning Android and I'm making an app which uses a XML file to store some info. I have no problem creating the file, but trying to read de XML tags with XPath (DOM, XMLPullParser, etc. only gave me problems) I've been able to read, at least, the first one. Let's see the code. Here is the XML file the app generates: <dispositivo> <id>111</id> <nombre>Name</nombre> <intervalo>300</intervalo> </dispositivo> And here is the function which reads the XML file: private void leerXML() { try { XPathFactory factory=XPathFactory.newInstance(); XPath xPath=factory.newXPath(); // Introducimos XML en memoria File xmlDocument = new File("/data/data/com.example.gps/files/devloc_cfg.xml"); InputSource inputSource = new InputSource(new FileInputStream(xmlDocument)); // Definimos expresiones para encontrar valor. XPathExpression tag_id = xPath.compile("/dispositivo/id"); String valor_id = tag_id.evaluate(inputSource); id=valor_id; XPathExpression tag_nombre = xPath.compile("/dispositivo/nombre"); String valor_nombre = tag_nombre.evaluate(inputSource); nombre=valor_nombre; } catch (Exception e) { e.printStackTrace(); } } The app gets correctly the id value and shows it on the screen ("id" and "nombre" variables are assigned to a TextView each one), but the "nombre" is not working. What should I change? :) Thanks for all your time and help. This site is quite helpful! PD: I've been searching for a response on the whole site but didn't found any.

    Read the article

  • Concise description of how .h and .m files interact in objective c?

    - by RJ86
    I have just started learning objective C and am really confused how the .h and .m files interact with each other. This simple program has 3 files: Fraction.h #import <Foundation/NSObject.h> @interface Fraction : NSObject { int numerator; int denominator; } - (void) print; - (void) setNumerator: (int) n; - (void) setDenominator: (int) d; - (int) numerator; - (int) denominator; @end Fraction.m #import "Fraction.h" #import <stdio.h> @implementation Fraction -(void) print { printf( "%i/%i", numerator, denominator ); } -(void) setNumerator: (int) n { numerator = n; } -(void) setDenominator: (int) d { denominator = d; } -(int) denominator { return denominator; } -(int) numerator { return numerator; } @end Main.m #import <stdio.h> #import "Fraction.h" int main(int argc, char *argv[]) { Fraction *frac = [[Fraction alloc] init]; [frac setNumerator: 1]; [frac setDenominator: 3]; printf( "The fraction is: " ); [frac print]; printf( "\n" ); [frac release]; return 0; } From what I understand, the program initially starts running the main.m file. I understand the basic C concepts but this whole "class" and "instance" stuff is really confusing. In the Fraction.h file the @interface is defining numerator and denominator as an integer, but what else is it doing below with the (void)? and what is the purpose of re-defining below? I am also quite confused as to what is happening with the (void) and (int) portions of the Fraction.m and how all of this is brought together in the main.m file. I guess what I am trying to say is that this seems like a fairly easy program to learn how the different portions work with each other - could anyone explain in non-tech jargon?

    Read the article

  • Yii Framework Tutorial - file not found

    - by Heshan Perera
    I am in the process of learning the Yii Framework. I have been following this Tutorial. I have followed all the steps and have by index page loading. In my index.php page I point to two other pages located in protected/views/message The following is the code in my index.php located in the message folder mentioned above. <html> <body> <h1>Welcome</h1> <p> To view our message go to... <?php echo CHtml::link('Here', '/message/show')?> </p> <p> To edit our message go to... <?php echo CHtml::link('Here', '/message/edit')?> </p> </body> </html> "message" is the ID I gave when generating the model and controller through the yii shell application. The problem is, after the above page loads, and I click on any one of the above URLs, it points to "localhost:8080/message/show" and "localhost:8080/message/edit" , whereas the real location of these files is "localhost:8080/test/protected/views/message/..." What could I be doing wrong ?

    Read the article

  • The question about the basics of LINQ to SQL working

    - by Alex
    I just started learning LINQ to SQL, and so far I'm impressed with the easy of use and good performance. I used to think that when doing LINQ queries like from Customer in DB.Customers where Customer.Age > 30 select Customer Get all customers from the database ("SELECT * FROM Customers"), move them to the Customers array and then make a search in that Array using .NET methods. This is very inefficient, what if there are hundreds of thousands of customers in the database? Making such big SELECT queries would kill the web application. Now after experiencing how actually fast LINQ to SQL is, I start to suspect that when doing that query I just wrote, LINQ somehow converts it to a SQL Query string SELECT * FROM Customers WHERE Age > 30 And only when necessary it will run the query. So my question is: am I right? And when is the query actually run? The reason why I'm asking is not only because I want to understand how it works in order to build good optimized applications, but because I came across the following problem. I have 2 tables, one of them is Books, the other has information on how many books were sold on certain days. My goal is to select books that had at least 50 sales/day in past 10 days. It's done with this simple query: from Book in DB.Books where (from Sale in DB.Sales where Sale.SalesAmount >= 50 and Sale.DateOfSale >= DateTime.Now.AddDays(-10) select Sale.BookID).Contains(Book.ID) select Book The point is, I have to use the checking part in several queries and I decided to create an array with IDs of all popular books: var popularBooksIDs = from Sale in DB.Sales where Sale.SalesAmount >= 50 and Sale.DateOfSale >= DateTime.Now.AddDays(-10) select Sale.BookID; BUT when I try to do the query now: from Book in DB.Books where popularBooksIDs.Contains(Book.ID) select Book It doesn't work! That's why I think that we can't use thins kinds of shortcuts in LINQ to SQL queries, like we can't use them in real SQL. We have to create straightforward queries, am I right?

    Read the article

  • Imlpementations of an Interface with Different Types?

    - by b3njamin
    Searched as best I could but unfortunately I've learned nothing relevant; basically I'm trying to work around the following problem in C#... For example, I have three possible references (refA, refB, refC) and I need to load the correct one depending on a configuration option. So far however I can't see a way of doing it that doesn't require me to use the name of said referenced object all through the code (the referenced objects are provided, I can't change them). Hope the following code makes more sense: public ??? LoadedClass; public Init() { /* load the object, according to which version we need... */ if (Config.Version == "refA") { Namespace.refA LoadedClass = new refA(); } else if (Config.Version == "refB") { Namespace.refB LoadedClass = new refB(); } else if (Config.Version == "refC") { Namespace.refC LoadedClass = new refC(); } Run(); } private void Run(){ { LoadedClass.SomeProperty... LoadedClass.SomeMethod(){ etc... } } As you can see, I need the Loaded class to be public, so in my limited way I'm trying to change the type 'dynamically' as I load in which real class I want. Each of refA, refB and refC will implement the same properties and methods but with different names. Again, this is what I'm working with, not by my design. All that said, I tried to get my head around Interfaces (which sound like they're what I'm after) but I'm looking at them and seeing strict types - which makes sense to me, even if it's not useful to me. Any and all ideas and opinions are welcome and I'll clarify anything if necessary. Excuse any silly mistakes I've made in the terminology, I'm learning all this for the first time. I'm really enjoying working with an OOP language so far though - coming from PHP this stuff is blowing my mind :-)

    Read the article

  • Why doesn't the SplitView iPhone template have a nib file for the RootView?

    - by Dr Dork
    I'm diving into iPad development and am learning a lot quickly, but everywhere I look, I have questions. After creating a new SplitView app in Xcode using the template, it generates the AppDelegate class, RootViewController class, and DetailViewController class. Along with that, it creates a .xib files for MainWinow.xib and DetailView.xib. How do these five files work together? Why is there a nib file for the DetailView, but not the RootView? When I double click on the MainWindow.xib file, Interface Builder launches without a "View" window, why? Below is the code for didFinishLaunchingWithOptions method inside the AppDelegate class. Why are we adding the splitViewController as a subview? (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after app launch rootViewController.managedObjectContext = self.managedObjectContext; // Add the split view controller's view to the window and display. [window addSubview:splitViewController.view]; [window makeKeyAndVisible]; return YES; } Thanks so much in advance for all your help! I still have a lot to learn, so I apologize if this question is absurd in any way. I'm going to continue researching these questions right now!

    Read the article

  • Can this be done using LINQ/Lambda, C#3.0

    - by Newbie
    Objective: Generate dates based on Week Numbers Input: StartDate, WeekNumber Output: List of dates from the Week number specified till the StartDate i.e. If startdate is 23rd April, 2010 and the week number is 1, then the program should return the dates from 16th April, 2010 till the startddate. The function public List<DateTime> GetDates(DateTime startDate,int weeks) { List<DateTime> dt = new List<DateTime>(); int days = weeks * 7; DateTime endDate = startDate.AddDays(-days); TimeSpan ts = startDate.Subtract(endDate); for (int i = 0; i <= ts.Days; i++) { DateTime dt1 = endDate.AddDays(i); dt.Add(dt1); } return dt; } I am calling this function as DateTime StartDate = DateTime.ParseExact("20100423", "yyyyMMdd", System.Globalization.CultureInfo.InvariantCulture); List<DateTime> dtList = GetDates(StartDate, 1); The program is working fine. Question is using C# 3.0 feature like Linq, Lambda etc. can I rewrite the program. Why? Because I am learning linq and lambda and want to implement the same. But as of now the knowledge is not sufficient to do the same by myself. Thanks.

    Read the article

  • Django Aggregation Across Reverse Relationship

    - by Tom
    Given these two models: class Profile(models.Model): user = models.ForeignKey(User, unique=True, verbose_name=_('user')) about = models.TextField(_('about'), blank=True) zip = models.CharField(max_length=10, verbose_name='zip code', blank=True) website = models.URLField(_('website'), blank=True, verify_exists=False) class ProfileView(models.Model): profile = models.ForeignKey(Profile) viewer = models.ForeignKey(User, blank=True, null=True) created = models.DateTimeField(auto_now_add=True) I want to get all profiles sorted by total views. I can get a list of profile ids sorted by total views with: ProfileView.objects.values('profile').annotate(Count('profile')).order_by('-profile__count') But that's just a dictionary of profile ids, which means I then have to loop over it and put together a list of profile objects. Which is a number of additional queries and still doesn't result in a QuerySet. At that point, I might as well drop to raw SQL. Before I do, is there a way to do this from the Profile model? ProfileViews are related via a ForeignKey field, but it's not as though the Profile model knows that, so I'm not sure how to tie the two together. As an aside, I realize I could just store views as a property on the Profile model and that may turn out to be what I do here, but I'm still interested in learning how to better use the Aggregation functions.

    Read the article

  • Message Handlers and the WeakReference issue

    - by user1058647
    The following message Handler works fine receiving messages from my service... private Handler handler = new Handler() { public void handleMessage(Message message) { Object path = message.obj; if (message.arg1 == 5 && path != null) //5 means its a single mapleg to plot on the map { String myString = (String) message.obj; Gson gson = new Gson(); MapPlot mapleg = gson.fromJson(myString, MapPlot.class); myMapView.getOverlays().add(new DirectionPathOverlay(mapleg.fromPoint, mapleg.toPoint)); mc.animateTo(mapleg.toPoint); } else { if (message.arg1 == RESULT_OK && path != null) { Toast.makeText(PSActivity.this, "Service Started" + path.toString(), Toast.LENGTH_LONG).show(); } else { Toast.makeText(PSActivity.this,"Service error" + String.valueOf(message.arg1), Toast.LENGTH_LONG).show(); } } }; }; However, even though it tests out alright in the AVD (I'm feeding it a large KML file via DDMS) the "object path = message.obj;" line has a WARNING saying "this Handler class should be static else leaks might occur". But if I say "static Handler handler = new Handler()" it won't compile complaining that I "cannot make a static reference to a non-static field myMapView. If I can't make such references, I can't do anything useful. This led me into several hours of googling around on this issue and learning more about weakReferences than I ever wanted to know. The often found reccomendation I find is that I should replace... private Handler handler = new Handler() with static class handler extends Handler { private final WeakReference<PSActivity> mTarget; handler(PSActivity target) { mTarget = new WeakReference<PSActivity>(target); } But this won't compile still complaining that I can't make a static reference to a non-dtatic field. So, my question a week or to ago was "how can I write a message handler for android so my service can send data to my activity. Even though I have working code, the question still stands with the suffix "without leaking memory". Thanks, Gary

    Read the article

  • Developing a 2D Game for Windows Phone 8

    - by Vaccano
    I would like to develop a 2D game for Windows Phone 8. I am a professional Application Developer by day and this seems like a fun hobby. But I have been disapointed trying to get going. It seems that 2D games (far and away the majority of games) do not have any real support. It seems the Windows Phone makers did not include support for Direct2D. So unless you are planning to make a fully 3D app, you are out of luck. So, if you just wanted to make a nice 2D app, these are your choices: Write your game using Xaml and C# (Performance Issues?) Write your game using Direct3D and but only draw on one plane. Use the DirectX Took Kit found on codeplex. It allows you to use the dying XNA framework's API for development. Number 3 seems the best for my game. But I hate to waste my time learning the XNA api when Microsoft has clearly stated that it is not going to be supported going forward. Number 2 would work, but 3D development is really hard. I would rather not have to do all that to get the 2D effect. (Assuming Direct2D is easier. I have yet to look into that.) Number 1 seems the easiest, but I worry that my app will not run well if it is based off of xaml rendering rather than DirectX. What is the suggested method from Microsoft? And who decided that 2D games were going to get shortchanged?

    Read the article

  • What are Sharepoint(MOSS 2007) Developement/Deployment best practices.

    - by Satish
    We are deploying sharepoint MOSS 2007 at our work. I'm trying to come up with a sharepoint development and deployment methodology. We have Dev/QA/Prod environments and I need a way, preferably automated to deploy changes from Dev to QA and from there to prod. We are creating site collections web parts etc. Some of it is done directly within sharepoint, some through Sharepoint designer or visual studio. I'm looking for a way to extract this and deploy it to other enviornments. I tried stsadm backup/restore import/export etc but they all move the data along with it as well. I just need the structure deployed. Content deployment paths and jobs does the same thing as well. We use MSBuild & Curisecontrol.net for other .net projects to automate build/deployment process. I'm looking for something similar with sharepoint if possible. What are your best practices for this? Since my team is learning we don't have a defined process and we are open to change our development process if needed.

    Read the article

  • The use of getters and setters for different programming languages [closed]

    - by leonhart88
    So I know there are a lot of questions on getters and setters in general, but I couldn't find something exactly like my question. I was wondering if people change the use of get/set depending on different languages. I started learning with C++ and was taught to use getters and setters. This is what I understand: In C++ (and Java?), a variable can either be public or private, but we cannot have a mix. For example, I can't have a read-only variable that can still be changed inside the class. It's either all public (can read and change it), or all private (can't read and can only change inside the class). Because of this (and possibly other reasons), we use getters and setters. In MATLAB, I can control the "setaccess" and "getaccess" properties of variables, so that I can make things read-only (can directly access the property, but can't overwrite it). In this case, I don't feel like I need a getter because I can just do class.property. Also, in Python it is considered "Pythonic" to not use getters/setters and to only put things into properties if needed. I don't really understand why its OK to have all public variables in Python, because that's opposite of what I learned when I started with C++. I'm just curious what other people's thoughts are on this. Would you use getters and setters for all languages? Would you only use it for C++/Java and do direct access in MATLAB and Python (which is what I am currently doing)? Is the second option considered bad? For my purposes, I am only referring to simple getters and setters (just return/set the value and do not do anything else). Thanks!

    Read the article

  • how do i call mpmovieplayer from applicationwillresignactive in ppdelegate

    - by ss30
    i'm using mpmovieplayer to play audio stream, one problem i'm having trouble with handling intruptions e.g when call is received. My player is declared in viewcontroller and i beleive i need to do something in applicationdidresignactive in my appdelegate right? how do i do that if my appdelegate isn't aware of my moviePlayer? i'm new to iphone dev so i'm learning as i go and enjoying it :) here is what i'm doing in viewcontroller -(IBAction)play1MButton:(id)sender{ [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayerStatus:) name:MPMoviePlayerPlaybackStateDidChangeNotification object:nil]; NSString *url = @"http://22.22.22.22:8000/listen.pls"; [self.activityIndicator startAnimating]; moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL URLWithString:url]]; [moviePlayer prepareToPlay]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(moviePlayerLoadStateChanged:) name:MPMoviePlayerLoadStateDidChangeNotification object:nil]; } } -(void) moviePlayerStatus:(NSNotification*)notification { //MPMoviePlayerController *moviePlayer = notification.object; MPMoviePlaybackState playbackState = moviePlayer.playbackState; if(playbackState == MPMoviePlaybackStateStopped) { NSLog(@"MPMoviePlaybackStateStopped"); } else if(playbackState == MPMoviePlaybackStatePlaying) { NSLog(@"MPMoviePlaybackStatePlaying"); } else if(playbackState == MPMoviePlaybackStatePaused) { NSLog(@"MPMoviePlaybackStatePaused"); } else if(playbackState == MPMoviePlaybackStateInterrupted) { NSLog(@"MPMoviePlaybackStateInterrupted"); } else if(playbackState == MPMoviePlaybackStateSeekingForward) { NSLog(@"MPMoviePlaybackStateSeekingForward"); } else if(playbackState == MPMoviePlaybackStateSeekingBackward) { NSLog(@"MPMoviePlaybackStateSeekingBackward"); } } - (void) moviePlayerLoadStateChanged:(NSNotification*)notification { if ([moviePlayer loadState] != MPMovieLoadStateUnknown) { [[NSNotificationCenter defaultCenter] removeObserver:self name:MPMoviePlayerLoadStateDidChangeNotification object:moviePlayer]; [moviePlayer play]; [self.activityIndicator stopAnimating]; [moviePlayer setFullscreen:NO animated:NO]; } } and in appdelegate - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch. self.window.rootViewController = self.viewController; [self.window makeKeyAndVisible]; AVAudioSession *audioSession = [AVAudioSession sharedInstance]; NSError *setCategoryError = nil; [audioSession setCategory:AVAudioSessionCategoryPlayback error:&setCategoryError]; if (setCategoryError) { } NSError *activationError = nil; [audioSession setActive:YES error:&activationError]; if (activationError) { } I can catch the errors but how do i use the player from appdelegate?!! thanks in advance

    Read the article

  • Memory management of objects returned by methods (iOS / Objective-C)

    - by iOSNewb
    I am learning Objective-C and iOS programming through the terrific iTunesU course posted by Stanford (http://www.stanford.edu/class/cs193p/cgi-bin/drupal/) Assignment 2 is to create a calculator with variable buttons. The chain of commands (e.g. 3+x-y) is stored in a NSMutableArray as "anExpression", and then we sub in random values for x and y based on an NSDictionary to get a solution. This part of the assignment is tripping me up: The final two [methods] “convert” anExpression to/from a property list: + (id)propertyListForExpression:(id)anExpression; + (id)expressionForPropertyList:(id)propertyList; You’ll remember from lecture that a property list is just any combination of NSArray, NSDictionary, NSString, NSNumber, etc., so why do we even need this method since anExpression is already a property list? (Since the expressions we build are NSMutableArrays that contain only NSString and NSNumber objects, they are, indeed, already property lists.) Well, because the caller of our API has no idea that anExpression is a property list. That’s an internal implementation detail we have chosen not to expose to callers. Even so, you may think, the implementation of these two methods is easy because anExpression is already a property list so we can just return the argument right back, right? Well, yes and no. The memory management on this one is a bit tricky. We’ll leave it up to you to figure out. Give it your best shot. Obviously, I am missing something with respect to memory management because I don't see why I can't just return the passed arguments right back. Thanks in advance for any answers!

    Read the article

  • identifier ... is undefined when trying to run pure C code in Cuda using nvcc

    - by Lostsoul
    I'm new and learning Cuda. A approach that I'm trying to use to learn is to write code in C and once I know its working start converting it to Cuda since I read that nvcc compiles Cuda code but complies everything else using plain old c. My code works in c(using gcc) but when I try to compile it using nvcc(after changing the file name from main.c to main.cu) I get main.cu(155): error: identifier "num_of_rows" is undefined main.cu(155): error: identifier "num_items_in_row" is undefined 2 errors detected in the compilation of "/tmp/tmpxft_00002898_00000000-4_main.cpp1.ii". Basically in my main method I send data to a function like this: process_list(count, countListItem, list); the first two items are ints and the last item(list) is a matrix. Then I create my function like this: void process_list(int num_of_rows, int num_items_in_row, int current_list[num_of_rows][num_items_in_row]) { This line is where I get my errors when using nvcc(line 155). I need to convert this code to cuda anyway so no need to troubleshoot this specific issue(plus code is quite large) but I'm wondering if I'm wrong about nvcc treating the C part of your code like plain C. In the book cuda by example I just used nvcc to compile but do I need any extra flags when just using pure c?

    Read the article

  • Why are (almost) all the on-line games written in ActionScript (Flash) not Java?

    - by MasterPeter
    I absolutely love good defender games (e.g. Gemcraft, Protector: reclaiming the throne) as they can be intellectually quite challenging; it's like playing chess but a little less thinking a bit more action. Sadly, there are not that many good ones out there and I thought I would create one myself and share it with the rest of the world by making it available on-line. I have never worked with ActionScript but when it comes to on-line games, this is the main choice. I have tried to find a decent 2D game in the form of a Java applet but to no avail. Why is this so? I could write the game, most comfortably, in Delphi for Win32 but then people would need to download the executable, which could deter some form downloading it, and also it would only work on Windows. I am also familiar with Java, having worked with Java for the last four years or so. Although I don't have much experience with games programming. Should I note be deterred by the fact that all online games are written for in Flash and create my defender game as a Java applet, or should I consider learning ActionScript and games development for the ActionScript Virtual Machine (AS3 looks very much like Java... but still, it's an entirely new technology to me and I might never use it professionally.) Could you, please, just answer the the question in the title? Why Flash, not Java applets? Is it only 'politics'?

    Read the article

  • jQuery Syntax Error - Trying to detect viewport size and select background image to use w/CSS

    - by CuppyCakes
    Hi all. Please be gentle, I'm still learning. I imagine that the solution to my problem is simple and that perhaps I have just been in front of the computer too long. I am trying to detect the size of the viewport, and then use a different sized image for a background on an element depending on the size of the viewport. Here is what I have so far: $(document).ready(function(){ var pageWidth = $(window).width(); if ( pageWidth <= 1280 ) { $('#contact').css('background-image', 'url(../images/contact_us_low.jpg)'); } elseif ( pageWidth > 1280 ) { $('#contact').css('background-image', 'url(../images/contact_us_high.jpg)'); } }); Error: missing ; before statement [Break on this error] elseif ( pageWidth 1280 ) {\n (Line 7) To me it seems like all of my semi-colons are in the right place. Two questions: Am I going about solving the problem in a sensible way? To me a simple conditional should solve this background problem, as the code is merely selecting between two images based on what size it detects the viewport to be. Can you please help point out my n00b syntax error? Sometimes it really does help to have an extra pair of eyes look at something like this, even if small. Thank you kindly for your advice, I will continue poking and perusing the docs I have available to me.

    Read the article

< Previous Page | 232 233 234 235 236 237 238 239 240 241 242 243  | Next Page >